DE2155109C3 - Process for the simultaneous production of 13-butadiene and methacrolein - Google Patents

Description

carries out, in which L phosphorus, arsenic and / or boron and Me means potassium, rubidium and / or cesium, while a to g indicate the number of atoms of the chemical elements concerned, with the proviso that for / = 12, a and b are independently numbers from 0 to 15, the sum of a + b has a value from 1 to 15, c a number from 0.5 to 7, your number from 0.1 to 4, g-a number from 36 to 98 , e is a number from 0 to 4 and h is a number from 0.1 to 1.0

2. The method according to claim 1, characterized in that a catalyst of the general formula I is used in which a is a number from 0 to 10, b is a number from 1 to 15, the sum a + b is a value of 4 to 12 has, c is a number from 1 to 5, d is a number from 1 to 3, e is a number from 0 to 2, f = 12, g is a number from 45 to 60 and h is a number from 0.01 to 1.0 .

3. The method according to claim 1, characterized in that a catalyst of the general formula I is used in which a is a number from 0 to 5, 6 is a number from 3 to 12, the sum a + b is a value of 4 to 12 is a number from 1 to 4, d is a number from 1 to 3, e is 0 or 1, f = 12, g is a number from 45 to 60 and Λ is a number from 0.01 to 0.5.

4. The method according to claim 1 to 3, characterized in that the catalyst in combination is used with a silica-containing carrier.

5. The method according to claim 1 to 4, characterized in that a catalyst of the formula I. the following composition is used, which before use at temperatures in Range of 650 to 800 ° C has been calcined:

a = 0, b = 1 to 15, c = 1 to 5, d = 1 to 3, e = 0 to 2, / ■ = 12, ^ = 45 to 60 and /? = 0.01 to O.l.

6. The method according to claim 1 to 5, characterized in that the oxidation ir presence is carried out by steam.

7. The method according to claim 1 to 7, characterized in that the molar ratio of oxygen to water vapor and total amount of olefins has values from 0.5 to 4: 1 to 20: 1.

8. The method according to claim 1 to 8, characterized in that the oxidation when pressing 0.5 to 10 atm absolute is carried out.

The oxidation of n-butenes or isobutylene is known per se. For example, one has 1,3-butadiene Made using a catalyst that contains nickel, cobalt, iron, bismuth, phosphorus and molybdenum contains (see Japanese patent application 26 842/1968). Also the production of methacrolein under The use of a corresponding catalyst is already known (see Japanese patent application 2 324/1968). The highest yield per run, which, however, according to the examples of these publications can be achieved is 83 percent for the production of 13-butadiene from butene-1 and r.ar 37 Percent for the production of methacrolein.

Furthermore, a process for the simultaneous production of methacrolein and 1,3-butadiene is known, which uses oxidic catalysts containing vanadium, bismuth and molybdenum (See Japanese Patent Application 7 881/1967). In this known method, however, are the yields obtained are not yet satisfactory. The highest methacrolein yield is only 67 percent and the highest yield of 1,3-butadiene about 76 percent

Surprisingly, it has now been found that 1,3-butadiene and methacrolein pass through at the same time catalytic oxidation from mixtures of butenes, namely butene-1, cis-2-butene and trans-2-butene, and Isobutylene can be produced in particularly high yield if the reaction is carried out in the presence special catalysts.

The invention thus relates to a process for the simultaneous production of 1,3-butadiene and methacrolein by reacting a gas mixture containing n-butenes and isobutylene with molecular oxygen in the presence of a molybdenum, bismuth, iron and an alkali metal containing catalyst at increased Temperatures, which is characterized in that the reaction in the presence of a catalyst empirical formula below

The invention relates to an improved process for the simultaneous production of 1,3-butadiene and methacrolein by treating mixtures containing n-butenes and isobutylene with molecular Oxygen.

carries out, in which L phosphorus, arsenic and / or boron and Me potassium, rubidium and / or cesium, while a to g indicate the number of atoms of the chemical elements concerned with the proviso that for f - 12, a and b independently of each other are numbers from 0 to 15, the sum of a + b has a value from 1 to 15, c is a number from 0.5 to 7, d is a number from 0.1 to 4, g is a number from 36 to 98, e is a number from 0 to 4 and h is a number from 0.01 to 1.0.

According to the invention, when using this special type of catalyst, 1,3-butadiene and methacrolein are used formed with high selectivity without excessive oxidation of the starting olefins used with the formation of undesirable oxidation products such as carbon monoxide, carbon dioxide, maleic acid and Acetic acid, takes place.

The catalysts used according to the invention differ in particular from those in Catalysts described above (Japanese Patent Application 26 842/1968 and 2 324/1968) that they contain small amounts of the component Me, i. H. Potassium, rubidium, or cesium. By this addition of the component Me, the selectivity is surprisingly with respect to the The formation of methacrolein and 1,3-butadiene is significantly improved

According to the invention, conversions per run under optimal working conditions of 90 up to 91 percent in relation to 1,3-butadiene and from 72 percent in relation to methacrolein («hold out Isobutylene).

According to the prior art where only a single Starting component has been implemented, namely either a mixture of n-butenes or isobutylene, it was first necessary to carry out a pre-cleaning physically or chemically, to separate isobutylene from the mixture of n-butenes. Currently being used in industrial Scale butene mainly obtained from Ci fractions, which are used in the cracking of crude oil Production of gasoline incurred. The 1,3-butadiene is extracted from these Cr fractions and then obtained the residue is a mixture of about four butenes, namely butene-1, cis-2-butene, trans-2-butene and isobutylene. These four butene isomers, however, show largely identical physical and chemical properties Properties, and therefore it presents considerable difficulties in separating the butenes from one another and the to clean the desired component accordingly. Hence it is a per se obtainable single isomer Component of butene for use as a starting material in any of the above Procedure far too costly.

In the process according to the invention, however, an end product is obtained which mainly consists of 1,3-butadiene and methacrolein. These two compounds have boiling points of 4 ° C and 68 ° C, respectively and can therefore be easily separated from one another using physical working methods.

The four butene isomers which are present in the butene mixtures used according to the invention as starting components generally show different reactivity, which increases in the following order: isobutylene-butene-1-cis-2-butene and trans-2-butene. However, the catalysts used in the invention have the special feature that the optimum reaction temperature of at least one such Butengemisches is the major components in approximately the same region, namely in the range of about 340-370 ⁰ C. This is especially true for butene-1 and isobutylene. These two main components of such isomer mixtures have an optimal reaction temperature which differs from one another by at most about 2 ° C. This fact is of great practical advantage because practically the same reaction takes place at approximately the same temperature with the same degrees of conversion. Accordingly, there are also no restrictions on the mixing ratio of the starting olefins, and the above-mentioned two butene isomers can therefore be used in any mixing ratio. This fact is also of particular advantage because unreacted starting material can be recycled back into the reaction zone without special precautionary measures, as a result of which the large-scale implementation is considerably simplified.

The catalysts used according to the invention are mixtures of compounds or Complexes, which consist of the oxides of the metals in question. The composition of the catalysts can be represented by the above formula I, which refers to the Oxidkom-ηΐπγ nHpr rin «i

OviH ho

In the context of the invention, preference is given to using catalysts of the general formula I given above, in which a is a number from 0 to 10, preferably 0 to 5, b is a number from 1 to 15. the sum a + b has a value from 4 to 12, c a number from 1 to 5, your number from 1 to 3, e a number from 0 to 2, / = 12, # a number from 45 to 60 and h a Number is from 0.01 to 1.0
However, im

Within the scope of the invention, catalysts of the above general formula I are used, in which a is a number from 0 to 5, in particular from 0 to 2, b is a number from 3 to 12, the sum a + b has a value from 4 to 12, c is a Number from 1 to 4, d is a number from 1 to 3, e is 0 or 1, / = 12, g is a number from 45 to 60 and h is a number from 0.01 to 0.5.

The catalysts which can be used according to the invention can be prepared very conveniently by adding aqueous solutions of the corresponding water-soluble salts of nickel and / or cobalt, iron, bismuth and at least one acid from the group consisting of phosphoric acid, arsenic acid and boric acid to another aqueous solution which contains ammonium molybdate as a mixture containing solutions of potassium nitrate, rubidium nitrate or cesium nitrate. The resulting slurry is very advantageously mixed with a carrier material, for example silica gel, silica sol, diatomaceous earth, carborundum or aluminum oxide. However, silica sol is particularly preferred for this purpose in the context of the invention. The mixture obtained in this way is, if desired, heated to remove the water and dried until a firm cake is formed. This solid cake is then calcined in air at elevated temperatures in the range from 500 to 80O ⁰ C for longer than 4 hours.

The catalysts used according to the invention are preferably calcined at high temperature in order to prevent excessive amounts of undesired oxides, such as carbon dioxide, from being formed during the subsequent reaction. In the context of the invention, very particular preference is given to using a catalyst of the formula I of the following composition, which has been calcined ^{at temperatures in the range from 650 to 800 ° C. before use:}

a = 0, 6 = 1 to 15, c = 1 to 5, d = 1 to 3, e = 0 to 2, / = 12, £ = 45 to 60 and Λ = 0.01 to 0.1.

These catalysts can be used in any physical form in the present invention

so processes can be used, for example in the form of grains or pellets. The catalytic treatment The starting olefin can be in a fixed bed reactor, in a fluidized bed or in a fluidized bed be performed. Air is generally suitable as molecular oxygen. But not only can it Oxygen alone but also a mixture of the same with an inert gas such as nitrogen or carbon dioxide, can be used. The diluent gas in question should, however, be within the scope of the invention

do implementation behave quite inert. The process according to the invention is expediently carried out at a temperature in the range from 250 to 450 ^° C. and at a pressure of 0.5 to 10 atmospheres absolute in the presence of steam. With such an Oxyda-

f> 5 tion in the presence of air and water vapor, the contact time of the gaseous starting materials is generally 0.5 to 10 seconds and preferably 1 hour

DPmpccon

In the context of the invention, moles of total butene fed in are 0.5 to 4.0 moles and preferably 1.6 to 2.8 mol of oxygen and 1 to 20 mol, preferably 2 to 6 mol of steam are used.

Degree of conversion (C)% = for the following exemplary embodiments the following evaluation factors are used for the evaluation:

Moles converted n-butenes or isobutylene
MoI fed n-butenes or isobutylene

100.

Selectivity to 1,3-butadiene (S)% =

Selectivity to methacrolein (S)% = moles of 1,3-butadiene obtained

Moles of converted n-butene
Moles of methacrolein obtained

- 100,

Moles of isobutylene converted, yield per pass in 1,3-butadiene or methacrolein = (S) (C)%

- 100.

The examples illustrate the invention. Examples 1 to 10

63.5 g of ammonium molybdate (NH ₄ J ₆ Mo ₇ O ₂₄ MH ₂ O are dissolved in distilled water. 1.7 g of orthophosphoric acid and 0.22 g of potassium nitrate are then added to this solution with heating and stirring. 90 g are then added Aqueous silica sol with a silica content of 20 percent was added.

In addition, solutions of 22.0 g of nickel nitrate Ni (NO ₃ J ₂ · 6 H ₂ O, 39.4 g of cobalt nitrate Co (NO _{3 I 2} · 6 H ₂ O and 36.6 g of ferric nitrate Fe (NO ₃ I ₃ · 9 H ₂ O in a little water. The last solution consists of 14.6 g of bismuth nitrate Bi (NO ₃ I ₃ · 5 H ₂ O in 30 ml of distilled water, which contains 3.5 ml of concentrated nitric acid all of these solutions are mixed with the solution described first, which contains the silica sol, with stirring.

The resulting slurry is heated and dried at 200 ⁰ C. After cooling, the solid cake is powdered, pelletized and 6 hours calcining in air at 700 ⁰ C. The catalyst obtained in this way has a composition which can be expressed using the following formula:

Table I.

Moles of 1,3-butadiene or methacrolein obtained
Moi fed n-butenes or isobutylene

About 150 ml of this catalyst are in a Filled reaction tube with an internal diameter of 21.6 mm. This reaction tube is then in put in a salt bath of molten potassium nitrate,

Which is maintained at a temperature of 320 to 35O ⁰ C Zf. The olefin mixture used as starting material had a composition, expressed as a mole fraction, of 0.485 of 1-butene (degree of purity: 98 percent, remainder 2-butenes) and 0.515 of isobutylene (purity 97.0 percent, remainder butanes). A gaseous mixture of these olefins, air and steam was passed in a molar ratio of 1: 7.6 to 15.2: 3.0 to 8 ° C. over the catalyst in the reaction tube with contact times of 2.0 to 3.5 seconds.

The reaction mixture withdrawn from the reaction tube was gas chromatographically as well as by Acid-base titration analyzed. The main products, in order of concentration, were 1,3-butadiene; Methacrolein; Carbon dioxide; cis and trans-2-butenes; Acetone; Carbon monoxide; Acetic acid; Aldehyde and Acrolein. In contrast, methacrylic acid was only formed in very small quantities. In the table below the results are summarized, which when varying the temperature of the salt bath and the molar ratio of air to steam to the starting olefins can be obtained.

example catalyst Molar ratio Tempe Famous Conversion Yield ever Selectivity (S), Meth No. composition the compo rature foresight degree (Q,% Passage,% % acro nents in of Time lone fed in salt Butene-1 iso 1,3-Bu- meth- 1,3-Bu Gas flow bath butylene tadien acro tadien C ₄ H ₈ : O ₂ : H _{2 O} · « lone (C) (Sec.)

1 Ni _2-5 Co ₄ 2 Fe _3-0 Bi _{] - (} 3 P ₀₅ K ₀₀₇ 4th Mon ₁₂ O ₅₄ 5 6th 7th 8th

2.2 1.9 3.2 2.5 1.6 2.2 2.2

5.0 5.0 5.0 6.2 6.2 6.2 5.0

2.2: 5.0

335 331 320 321 345 280 360 380 2.7
3.1
2.3
2.6
2.9
3.5
2.4
2.0

98.2
95.5
98.3
97.5
95.0
89.3
97.6
98.5

98.0
94.3
97.5
96.2

93.8
86.2
96.8
98.8

91.5
88.3
89.2
91.2
90.3
83.8
89.3
87.1

71.2
67.7
68.5
70.3

62.1
63.5
64.8
61.3

93.2
92.5
90.7
93. "
92.7
93.8
91.5
89.0

72.6
71.8
70.2
69.6
66.2
73.6
67.0
62.0

Kalalvsalor 7th composition Β '|. () Ρ (Ι.5Ί 2 Molar ratio 1 55 109 Butene-1 (Sec.) Iso- 8th Meth Selectivity (.V). Meth I. the compo 3.0 95.2 null acro "... acro nents in 2.3 93.5 lone lone - MOpO ₅₄ fed in Tempe 2.5 96.0 U-Bu- continuation Gas flow rature 94.0 66.8 Ltdien 71.0 example C, I Ik :() · .: If, O of 92.2 Yield ie 67.8 73.6 No. salt Calming transformation 99.8 Passage. % 41.2 41.3 1: 2.2: 3.0 bad it degree (C 93.0 NJj ₅ Co ₄₅ F ,,, 1: 2.2: 8.0 Time U-Bu- 91.0 1: 2.2: 6.2 (O Uidien 85.9 340 340 9 315 88.5 10 85.0 Ver 82.5 casting example

Molar ratio of butene-I: isobutylene = I: 1.16.

Comparative example

A catalyst was prepared in the same manner as described above for Examples 1 to 10 has been described In this case, however, no potassium compound was added to the catalyst mixture added, d. h, in the formula given above for the catalyst composition, Λ has the value 0. The other reaction conditions are practically the same as in Examples 1 to 10. The in this Results obtained in the comparative experiment are also included in Table I above.

Examples 11-21

In the procedure of Examples 1 to 10, the catalyst composition was varied as shown in Table II below. The number of phosphorus atoms (e) and the number of potassium or cesium atoms (h) were varied. The starting butene mixture had a composition, expressed as a mole fraction, of 0.48 in terms of 1-butene and 030 in terms of isobutylene, the remainder being butanes. The molar ratio of butenes to oxygen to water vapor was in each case 1: 2.2: 5.0.

Table Il

Example no. Value for P e or K Λ, C _s temperature Degree of conversion (O, Isobutylene Yield ever Meth of the salt % Passage,% acro bath lone Butene-1 94.8 1,3-butadiene 67.3 97.4 66.5 (C) 96.5 64.5 11th 1.0 0.1 - 340 95.3 99.5 88.9 63.5 12th 1.0 0.2 - 345 95.5 92.7 87.0 60.4 13th 1.0 0.3 - 345 94.5 98.5 84.9 62.5 14th 0.5 0.02 - 328 96.0 97.0 82.3 69.8 15th 0.5 0.8 - 355 95.5 94.2 85.1 65.7 16 3.0 0.07 - 328 96.0 93.0 84.2 62.2 17th 0.0 0.07 - 348 96.5 94.8 87.3 71.2 18th 0.5 - 0.3 345 95.0 95.8 86.1 70.3 19th 0.5 - 0.5 350 95.5 84.7 20th - 0.07 - 345 95.5 90.3 21 - 0.1 - 348 96.3 89.5

If you in Example 13 of the table above, the potassium component by the corresponding Replaced the amount of rubidium, practically identical results are obtained.

Examples 22-25

In these examples, instead of 65, the catalyst contained reaction conditions corresponding to those of

of phosphorus arsenic. Otherwise, the catalyst was Example 1. The results obtained here are

but the same composition as those summarized in Table HI below Examples 1 to 10 above. Also the others

Table III

ίο

Example catalyst composition

Ni

Co le

Bi

As

Degree of conversion (Cl, yield per% passage,%

Mo butene-1 isobutylene 1,3-bula- meth-

dien acro

lone

22nd 4.5 4th 1 23 4.5 4th I. 24 3.0 2 2 25th 0 7th ->
J)

0.5 0.5 0.5

If you look at the example! ! 4 of the table above replaces the arsenic with the same amount of boron, this gives practically identical results.

B e i s ρ i e 1 e 26 to 37

In these examples, the atomic ratio of nickel, cobalt and iron with respect to bismuth varies. Otherwise, however, the same procedures were

12th
12th
12th
12th

94.3
93.2
96.0
96.5

94.0
92.7
95.1
94.8

88.0 86.2 90.0 90.8

61.8 63.9 68.0 67.5

Conditions applied as in Example 1. The results obtained are summarized in Table IV below.

Since in these examples the atomic ratio of phosphorus to potassium to molybdenum was kept at a constant value of 0.5: 0.07: 12, the relevant numerical values for the composition of the catalyst are omitted in Table IV .

Table IV Catalyst composition Co Fe Bi Conversion gray (Cl,% Isobutylene Yield ever Meth example Passage,% acro No. Ni Butene-I 1,3-butadiene lone 12th 3 I. 90.5 68.2 8th 5 I. 96.0 67.5 0 4.5 3 1 92.5 94.5 84.8 69.0 26th 0 1 3 1 96.5 95.5 89.7 61.3 27 0 5 2 1 96.0 95.0 90.4 65.5 28 10 8th 3 1 96.0 95.5 85.5 69.2 29 5 8th 1 1 95.5 92.5 85.7 64.2 30th 1 5 2 0.5 96.0 91.5 89.7 62.4 31 0 5 3 0.5 94.5 97.0 85.0 67.5 32 2.5 7th 3 0.5 93.0 96.4 85.0 68.4 33 1 8th 3 2 97.5 95.5 91.0 69.0 Ί4 0 8th 3 3 96.5 95.0 91.3 65.5 35 0 96.0 90.5 36 0 96.5 89.7 37

B e ι s ρ ι e 1 e 38 and 39 catalyst passed from Example 1, the molar ratio

In the preceding Examples 1 to 37 that was the total butene to oxygen to water vapor Ratio of 1-butene to isobutylene 1: 1.16. In that, however, it was again 1: 2 ^: 5.0. The received

Examples 38 and 39 described below. 55 results are summarized in Table V below.

different butene mixtures were taken over the

Table V composition
of the starting material
Butene-I isobutylene temperature
of
Salt bath
(C) Degree of conversion (Q,%
Butene-1 isobutylene 96.3
97.5 Yield ever
Passage,%
1,3-butadiene Methacro
lone Example no. 2 1
1 2 324
342 97.5
98.0 92.5
92.3 71.8
70.7 38
39

Examples 40 and 41

In the following Table VI results of two examples are given in which mixtures of cis-2-butene and isobutylene or from trans-2-butene and isobutylene were used as starting material. That molar ratio of the total amount of butenes to oxygen to water vapor was 1: 2.2: 5.0. That The ratio of the butenes to isobutylene was in each case 1: 1.6. Otherwise, the catalyst composition was the same as used in example 1.

Tabel Vl temperature
of the salt bath
(t) Degree of conversion (C). %
cis- or trans-2-butene Isobutylene Yield ever
1,3-BuUidien Passage,%
Methacro
lone example No. 405
410 cis-2-butene-91.5
trans -2-butene-88.5 98.2
99.0 80.5
76.5 57.0
52.5 40
41

B e i s ρ i e 1 42 to 44

Example 42 of Table VII, below, relates to the use of a spent butane-butene fraction as starting material which is 27.5 percent butene-1, 48.1 percent isobutylene, 8.6 percent trans-2-butene, 5.6 percent cis -2-butene and also contains 9.0 percent butane. This starting mixture is passed over the catalyst from Example 1 at a temperature of 360 to 370 ^° C., the contact time being set to 3.2 seconds. The following Examples 43 and 44, which are also listed in Table VII, on the other hand, illustrate the influence of a change in the total pressure of the reaction system.

As the reported results show, the catalysts according to the invention do not show any Reactivity with respect to the butanes contained in the starting material.

Tabel VII pressure
(atm.abs) Degree of conversion (C),%
η-butene isobutylene 98.8
97.3
96.5 Yield ever
1,3-butadiene Passage,%
Methacro
lone example No temperature
of the salt bath
(C) Atmospheric pressure
2
3 81.9
82.5
81.0 72.1
70.5
69.8 67.8
65.9
62.9 42
43
44 362
365
370

Claims (1)

Patent claims: t. Process for the simultaneous production of 13-butadiene and methacrolein by reaction a gas mixture containing n-butenes and isobutylene with molecular oxygen in the presence a catalyst containing molybdenum, bismuth, iron and an alkali metal at elevated temperatures, characterized in that the reaction is carried out in the presence of a catalyst empirical formula